Anechoic chamber design using ray tracing and theory of images

A ray-tracing technique which was used to help find the best possible anechoic chamber design in the frequency range of 30 MHz to 300 MHz is discussed. The electromagnetic fields due to a source inside the chamber are calculated. The scattered field is compared to the free space field to calculate the performance of the anechoic chamber in free space. The chamber is modeled as a rectangular cavity having walls made of lossy dielectric material. An electric dipole is used as a real model for actual currents on metallic surfaces. Fresnel reflection analysis is made with the electric field resolved into its components. The directions at which rays will leave the source are calculated using the theory of images. A numerical example of the technique is given